JPH0361629A - Control for control valve of on-vehicle engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for controlling control valves such as throttle valves and choke valves, which adjust the amount of air-fuel mixture and air supplied to a vehicle engine, using a step motor.

[Conventional technology]

The throttle shaft of a vehicle engine's throttle valve is connected to the accelerator pedal by a throttle wire, and while it rotates in the opening and closing directions when the accelerator pedal is operated, it is also controlled to rotate in the closing direction when driven by a step motor. A technique has been proposed. By rotating the throttle valve in the opening and closing directions, the throttle valve controls so that the appropriate amount of air-fuel mixture is supplied to the engine, and in order to perform this control, the throttle valve stops at a predetermined opening, Alternatively, it is driven to rotate from a stopped state to another opening degree. Conventionally, the step motor for driving the throttle valve has been controlled by energizing a pulse with a constant duty ratio (for example, 50%) regardless of whether the motor is stopped or in operation.

[Problem to be solved by the invention]

The reason why the step motor is always driven with a constant duty ratio as in the past is to output the torque that rotates the control valve. However, compared to the torque required to rotate the control valve, the torque required to maintain the control valve in the stopped state is small, and when the duty is set as a standard for the rotation of the control valve, the torque required to maintain the stopped state is excessive. This results in a high duty ratio, which results in a waste of electrical energy.

In particular, since the step motor uses an on-vehicle battery as a power source and the battery capacity is small, such wastage of electric energy is undesirable as it leads to a drop in battery voltage.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a control method that can prevent the electric energy of the step motor from being consumed.

[Means to solve the problem]

The control method of the present invention is a method in which a control valve of an on-vehicle engine energized by a spring is driven by an output torque generated by energizing a step motor, in which a control valve corresponding to the torque required for a stopped state and the torque required for an operating state of the control valve is provided. The present invention is characterized in that the duty ratio of the pulses of the step motor is switched between a stopped state and an activated state of the control valve.

[Operation] In the above configuration, the duty ratio of the drive pulse of the step motor is switched between the stopped state and the operating state of the control valve, so the duty ratio in the stopped state can be reduced.

〔Example〕

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings. First, in FIGS. 1, 2, 3, and 4,
A throttle shaft 2 is rotatably supported on a throttle body 1 serving as a support via bearings 3 and 4, and an intake passage 5 formed in the throttle body 1 is connected to the throttle shaft 2 to open and close it. A butterfly type throttle valve 6 is fixed.

Both ends of the throttle shaft 2 protrude from the throttle body 1 on both sides, and one end of the throttle shaft 2 protruding from the throttle body 1 (the left end in FIG. 3) has a 10th
A stroke motion lever 7 is fixed, and an operating lever 8 is rotatably supported. Also, the other end (third end) of the throttle shaft 2 protruding from the throttle body 1
A control lever 9 is fixed to the right end (in the figure).

At the one end of the throttle shaft 2 protruding from the throttle body 1, an engaging portion 2a having one flat surface is formed along the axis. The retaining portion 2a includes a cylindrical collar 10 whose inner end is in contact with the bearing 3, and a collar in order from its inner end, that is, the end closer to the throttle body 1, to its outer end, that is, the end that is farther from the throttle body 1. 10, a cylindrical collar 12 whose inner end is in contact with the regulation plate, and a tenth motion lever 7 which is in contact with the outer end of the collar 12. They are mated.

A nut 13 is screwed onto the outer end of the throttle shaft 2 protruding from the tenth motion lever 7, and a collar 10
, a regulating plate 11, a collar 12, and a tenth motion lever 7 are fixed to the throttle shaft 2.

The operating lever 8 has a cylindrical portion 8 that coaxially surrounds the collar 10.
a, and a drum part 8b fixed to the outer end of the cylindrical part 8a, and the cylindrical part 8a is connected to the collar 1 through a bearing 14.
It is pivoted by 0.

Further, the axial position of the cylindrical portion 8a is regulated by a member 15 and a regulating plate 11 when the synthetic resin material is in contact with the outer surface of the throttle body 1. A throttle wire 16 that is pulled and driven by a throttle operation unit such as an accelerator pedal (not shown) is wound around the drum portion 8b, and an engagement piece 17 provided at one end of the throttle wire 16 engages with the drum portion 8b. There is. Therefore, the operating lever 8 is rotated in the throttle valve opening direction shown by the arrow 18 in FIG. 2 by the pulling operation of the throttle wire 16 in response to the operation of the accelerator pedal. Note that, as mentioned above, the collar 10 was not fixed to the throttle body 1 but to the throttle shaft 2, and the cylindrical portion 8a of the operating lever 8 was pivotally supported to the collar 10 via the bearing 14, so it is assumed that the bearing 14 is stuck. Even in this case, the operating lever 8 can rotate integrally with the throttle shaft 2. In other words, reliable operation of the operating lever 8 is ensured.

A cylindrical portion 8a is located between the drum portion 8b and the throttle body 1.
A coiled first return spring 19 surrounding the control lever 8 is interposed, and this first return spring 19 moves the operating lever 8 in the direction indicated by the arrow 1.
The throttle valve is energized in the throttle valve closing direction 20, which is opposite to the direction 8.

Between the operation lever 8 and the tenth motion lever 7, a tenth motion lever 7 is provided between the operation lever 8 and the tenth motion lever 7.
and the 10th motion lever 7
A lost motion mechanism A is provided to prevent forced rotation of the throttle valve in the throttle valve closing direction 20 from affecting the operation of the operating lever 8. Lost motion mechanism A
These are engagement arm portions 21a and 21b provided on the drum portion 8b of the operation lever 8, and engagement arm portions provided on the tenth stroke motion lever 7 to engage with the engagement arms 21a and 21b, respectively. 22a, 22b, and a tenth motion spring 23 interposed between the operation lever 8 and the tenth motion lever 7, and the retaining arms 21a, 22g are
They are biased by a tenth motion spring 23 in the direction of mutual engagement.

Further, a second return spring 24 is interposed on the outside of the tenth motion spring 23 to bias the operating lever 8 in the throttle valve closing direction 20.

Tenth motion spring 23 and second return spring 24
is formed into a coil shape, and the collar 12 is coaxially surrounded and arranged between the member 25a, which is in contact with the tenth stroke engine lever 7, and the member 25b, which is in contact with the regulation plate 11. has been done. The receiver is member 25a, 25b is collar 1
The tenth motion spring 23 has a receiver in the inner cylinder of members 25g and 25b, and the second return spring 24 has a receiver in the member 25a. , 25b, respectively. As shown in FIG. 6, a plurality of notches 25a' and 25b' extending in the circumferential direction and the axial direction are formed in the double cylindrical parts of the members 25a and 25b, respectively, so that the surfaces of the inner and outer cylinders and the lost motion Reducing the sliding resistance of the lost motion spring 23 and the second return spring 24 by reducing the contact area with the spring 23 and the second return spring 24, and when dust gets caught in the lost motion spring 23 and the second return spring 24. Efforts are being made to ensure a place for dust to escape. In this embodiment, as shown in FIG. 3, the receiver connects members 25a and 25b to the throttle shaft 2
are separated in the axial direction, but the receivers are members 25a and 25b.
may be butted against each other in the axial direction of the throttle shaft 2. By butting the two together, the lost motion spring 23,
The deformation of the second return spring 24 during operation prevents the two springs from jamming into each other.

One end 23a of the tenth motion spring 23 engages with the engagement arm H22a of the tenth motion lever 7, and the other end 23b engages with the engagement arm 21a of the drum portion 8b. Further, one end 24a of the second return spring 24 is connected to the engaging arm portion 21a.
The other end 24b is engaged with the throttle body 1.

According to such a lost motion mechanism A, the operating lever 8 is moved in the throttle valve opening direction 1 against the biasing forces of the first and second return springs 19.24 by operating the accelerator pedal.
8, the tenth stroke motion lever 7 rotates in the throttle valve opening direction 18 due to the biasing force of the tenth stroke motion spring 23, and the throttle shaft 2 rotates in the direction to open the throttle valve 6. Further, when the operating lever 8 is rotated in the throttle valve closing direction, the engaging arms 21a, 2
1b is a retaining arm portion 22a.

22b, the tenth motion lever 7 and the throttle shaft 2 move in the throttle valve closing direction 20.
Rotate to. As mentioned above, by providing two sets of retaining parts for the operating lever 8 and the lost motion lever 7,
Even if one of the engaging portions becomes disengageable for some reason, the engagement between the operation lever 8 and the lost motion lever 7 is ensured by the other retaining portion. In other words, the reliability of rotation of the throttle shaft 2 by the rotation operation of the operating lever 8 is improved.

A bracket 26 is fixed to the throttle body 1. A cylindrical support portion 26a having an axis parallel to the throttle shaft 2 is formed in the bracket 26, and a detection shaft 27 is rotatably supported by the cylindrical support portion 26a.

The detection shaft 27 has a second shaft connected to the operating lever 8.
A zero stroke motion lever 28 is rotatably supported. At the outer end of the detection shaft 27 protruding from the 20th stroke motion lever 28, that is, at the end farthest from the throttle body 1, a small-diameter male screw portion 27a with a substantially rectangular cross section is coaxially formed with a step portion 27b interposed therebetween. ing. Male thread part 27a
passes through two detection levers that can be engaged with the 20th stroke motion lever 28 in a relatively unrotatable manner, and the detection lever 2
The two detection levers are fixed to the detection shaft 27 by tightening the nut 30 screwed onto the male screw 27a protruding from the shaft and pressing the detection lever 29 against the stepped portion 27b.

The 20th stroke motion lever 28 includes a cylindrical portion 28a surrounding the detection ITo 27, and a disk portion 28 fixed to the inner end of the cylindrical portion 28a, that is, the end closer to the throttle body 1.
b, and is rotatably attached to the detection shaft 27 between the outer end of the cylindrical support portion 26a of the bracket 26, that is, the end farthest from the throttle body 1, and the detection lever 29. The disk portion 28b of the 20th stroke motion lever 28 and the drum portion 8b of the operating lever 8 are interlocked and connected to each other via a cam mechanism B. This cam mechanism B includes an engagement pin 2 provided on an arm portion 28bl extending from the outer end side of the disc portion 28b, that is, the end side far from the throttle body.
8b1□, the first cam 31a that extends to the outer end of the drum portion 8b, that is, the end farthest from the throttle body, to engage with the engagement pin 28b1□, and the inner end of the disc portion 28b, that is, the throttle body. An engaging pin 28b2□ provided on the arm portion 28b protruding toward the closer end, and a second protruding toward the inner end of the drum portion 8b, that is, the end closer to the throttle body, to engage with the engaging pin 28b2°. It consists of a cam 31b. The cam mechanism B connects the levers 8 and 28 so that the 20th stroke motion lever 28 is rotated in the direction in which the accelerator pedal is depressed, as indicated by the arrow 32, in response to the rotation of the operating lever 8 in the throttle valve opening direction 18. It is something. In the cam mechanism B, unlike the case of a rod link, there is a driving joint, that is, the operating lever 8, and a driven joint, that is, the second
Since the zero stroke lever 28 can be separated, a high degree of freedom can be obtained in designing the interlocking/coupling mechanism between them.

Also, two cams 31a and 31b are provided, and when the rotation angle of the operating lever 8 in the throttle valve opening direction 18 is small, the cam 31a is used, and when the rotation angle is large, the cam 31a is used.
Since the 20th stroke motion lever 28 is rotated in the accelerator pedal depression direction 32 via the lever 1b, a linear relationship between the rotation of the operating lever 8 and the rotation of the 20th stroke motion lever 28 is ensured. Although the number of cams is two in this embodiment, by providing more cams, it is possible to further improve the linear relationship between the rotation of the operating lever 8 and the rotation of the 20th stroke motion lever 28. can.

As shown in FIGS. 1 and 2, the bracket 26 includes an engagement pin 33 having an axis parallel to the cylindrical support portion 26a.
is installed between the engaging pin 33 and the detection lever 28, and a 20th motion spring 35 is interposed between the engagement pin 33 and the detection lever 28, which biases the two detection levers and thus the detection shaft 27 to rotate in the return direction 34 of the accelerator pedal. has been done. The 20th motion spring 35 is formed into a coil shape surrounding the cylindrical support portion 26a, and one end 35a thereof engages with the detection lever 29, and the other end 35a engages with the engagement pin 33.

The disc portion 28b of the 20th stroke motion lever 28 is provided with an engaging portion 36, and the detection lever 29 is provided with an engaging portion 37 that can be engaged with the engaging portion 36. The retaining portion 37 is biased in the direction of engagement with the engaging portion 36 by a 20th motion spring 35 interposed between the detection lever 29 and the engaging pin 33.

Therefore, when the 20th stroke motion lever 28 is rotated in the accelerator pedal depression direction 32 as the operating lever 8 is rotated in the throttle valve opening direction 18, the engaging portion 3
6 and 37, the detection lever 29 rotates in the accelerator pedal depression direction 32 while overcoming the biasing force of the 20th stroke motion spring 35, and when the operating lever 8 is rotated in the throttle valve closing direction 20. , detection lever 29
is the 20th motion spring under the force of the 20th motion spring 35.
The accelerator pedal is rotated in the return direction 34 while pressing the stroke motion lever 28, and the two detection levers and, as a result, the detection shaft 27 are rotated in accordance with the amount of rotation of the operating lever 8, that is, the amount of accelerator operation. On the other hand, an accelerator pedal operation amount detector 38 is fixed to the bracket 26 facing the inner end of the detection shaft 27, that is, the end closer to the throttle body 1, and a lever 39 fixed to the inner end of the detection shaft 27 is connected to the accelerator pedal. It is connected to a manipulated variable detector 38.

The other end of the throttle shaft 2 protruding from the throttle body 1 is fixed to the throttle body 1 and pivoted to a cylindrical collar 41 whose inner end abuts the bearing 4. The control lever 9 is fixed to the protruding end of the throttle shaft 2. Also color 41
A driven gear 43 is rotatably supported through a bearing 42 . With this configuration, even if the bearing 42 is stuck, the driven gear 43 can be rotatably supported on the throttle shaft 2. For example, when the driven gear 43 is supported on the throttle shaft via a bearing, the throttle shaft and the driven gear become one body due to the fixed bearing, and the driven gear and other gears connected to it become resistive. As a result, rotation of the throttle shaft, that is, rotation of the throttle valve becomes impossible. However, with the above-described configuration, such a situation can be avoided. Furthermore, by configuring the collar 41 separately from the throttle body 1, the former can be constructed of a more appropriate material different from the latter, such as a material with high wear resistance, and even if the collar 41 is supported, the collar 41 Repairs can be easily performed by simply replacing parts.

A third return spring 44 is interposed between the driven gear 43 and the throttle body 1, and the driven gear 43 is rotationally biased in the throttle valve closing direction 18 by the third return spring 44, and the control lever 9 is engaged in. In addition, the driven gear 43
The outer surface, that is, the end surface on the side far from the throttle body 1, is in contact with the regulating plate 101 fixed to the collar 41, and the driven gear 43 is biased in the axial direction by the third return spring 44. It is supported in the thrust direction by a regulating plate 101, and its axial position is regulated.

A bracket 45 is fixed to the outer surface of the throttle body 1, and forms a gear box 102 that accommodates the driven gear 43, an intermediate gear 49, and a drive gear 54, which will be described later.

A throttle opening detector 46 is supported and fixed to the bracket 45 at a position opposite to the other end of the throttle shaft 2. A fixed lever 47 is connected to the lever 9.

Therefore, the amount of rotation of the throttle shaft 2, that is, the opening degree of the throttle valve 6 is detected by the throttle opening degree detector 46.

A support shaft 48 having an axis parallel to the throttle shaft 2 is supported between the throttle body 1 and the bracket 45. An intermediate gear 49 that meshes with the wave gear 43 is connected to a bearing 50 on the support shaft 48. It is rotatably supported through. A spring 51 is interposed between the intermediate gear 49 and the outer surface of the throttle body 1, and the intermediate gear 49 is urged in the axial direction by the spring 41, and the bracket 45 is supported in the thrust direction. Its axial position is regulated.

As mentioned above, the driven gear 43 meshes with the four intermediate gears.
is energized in the axial direction and supported in the thrust direction with a similar configuration, and its axial position is regulated, so that play in the axial direction of both gears 43 and 49 can be prevented, and By arranging both gears 43 and 49 so that their axial positions match, it is possible to ensure that both gears 43 and 49 mesh over the entire tooth surface, thereby preventing the generation of noise and uneven wear of the gears. I can do it.

A step motor 52 as an actuator is supported and fixed to the motor support portion 45a of the bracket 45, and its output shaft 53 is supported via a bearing 103. In this way, by supporting the output shaft 53 of the step motor 52 with the bracket 45, the motor flange, which was conventionally required as a part of the step motor, can be omitted.Therefore, by reducing the number of parts, the manufacturing cost of the throttle body can be reduced. can be reduced. in this case,
The arrangement of the step motor 52 on the throttle body 1 is as follows:
This is done by sequentially assembling the components of the step motor 52 to the bracket 45.

A drive gear 54 is attached to the output shaft 53 of the step motor 52.
is fixed, and the four intermediate gears are meshed with the drive gear 54. Therefore, the output shaft 53 of the step motor 52
is connected to the throttle shaft 2 via a drive gear 54, an intermediate gear 49, a driven gear 43, and a control lever 9 engaged with the driven gear 43. That is, by operating the step motor 52 when the throttle shaft 2 is rotated by the accelerator pedal operation and the throttle valve 6 is opened to a certain opening degree, the throttle valve 6 is moved in the closing direction regardless of the accelerator position. Rotationally driven.

When the throttle valve 6 is rotated in the closing direction by the operation of the step motor 52, the throttle shaft 2 is rotated against the engagement arm bracket 2 against the spring force of the tenth motion spring 23.
Since the throttle wire 16 is rotated in the throttle valve closing direction 20 while separating the wires 1 and 22 from each other, the throttle wire 16 is not affected.

Further, as shown in FIG. 7, a recess 104 is provided on the outer surface of the bracket 45 at a position facing the intermediate gear 49, and an adjustment screw 105 of the intermediate gear 49 is screwed into this recess 104. Furthermore, the fourth part 104 has an adjustment screw 1.
A plug cap 106 is fitted to cover 05. The adjustment screw 105 is adjustable in forward and backward positions, and when its tip comes into contact with the intermediate gear 49 at a predetermined circumferential position, the return side stop position of the step motor 52 is regulated, and the pulse of the step motor 52 is controlled. The adjustment is made so that the relationship between the number and the rotation angle of the throttle shaft 2 is uniquely determined. With the above configuration, the step motor 52
If the stop position on the return side is shifted, simply turn the adjusting screw 105 from the outside! In addition to being able to easily perform the adjustment, the plug cap 106 protects the inside from water and dust, thereby preventing adverse effects on the accuracy, durability, etc. of the step motor 52.

Further, the bracket 45 is provided with a chamber 107 vertically below the gear box 102, and this chamber 107 has first to third drain holes 108a, 108b.
and 108C, it communicates with the inside of the gear box 102, the step motor 52, and the atmosphere, respectively. With this configuration, even if moisture in the air condenses inside the gear box 102 or the step motor 52 due to temperature changes caused by the operation of the step motor 52 or the operation of the engine, this condensation can be removed through the drain holes 108a and 108b. Since the water can be introduced into the chamber 107 through the drain hole 108c and discharged into the atmosphere through the drain hole 108c, it is possible to appropriately prevent moisture and impurities contained therein from having a negative effect on the step motor 52 and the gear mechanism. can. Also, water should not directly enter the step motor 52 etc. from the outside.
This can be prevented by the intervention of 07. Furthermore, by setting the volume of this chamber 107 to a value commensurate with the amount of breathing inside the gearbox 102 (for example, approximately one-third of the space volume inside the gearbox 102), the inside of the gearbox is cooled and the outside air is absorbed. It is possible to prevent water from being sucked into the gear box when suctioning water, and the above effect can be obtained with a minimum chamber volume.

The clay wall of the bracket 45 is further provided with a ventilation hole 109 that communicates with the gear box 102 and is released to the atmosphere through a filter (not shown) such as an air cleaner installed in the intake system of the vehicle engine. . The ventilation hole 109 ensures ventilation inside the gearbox 102, and water, fuel, dust, etc. pass through the ventilation hole 109 to the gearbox 102 and the step motor 52 leading thereto.
A filter can prevent it from entering the body.

Further, since the vent hole 109 functions as a vent hole during the water draining, this water draining action can be performed smoothly. In this case, if the dimensional relationship between the water drain hole 108C and the ventilation hole 109 is appropriately set, the water drain function can be performed more smoothly.

A dashbot 56 is supported and fixed to the throttle body 1 to slow down the rotational movement of the tenth stroke motion lever 7 supported on the throttle shaft 2 in the throttle valve closing direction 20 near the fully closed position. ing. This dashbot 56 is conventionally known and consists of a housing 57 and a diaphragm 60 whose periphery is held between the housing 57 and which divides the interior of the housing 57 into a suction chamber 58 and five atmospheric pressure chambers. At the center, one end of a connecting rod 61 that movably passes through the housing 57 on the atmospheric pressure chamber 59 side and extends outward is connected to the retainer 8.
Connected via 0. A suction pipe 81 communicating with the suction chamber 58 is connected to the housing 57, and this suction pipe 81 is exposed to the atmosphere via a jet 82 at its tip. Therefore, when an attempt is made to drive the connecting rod 61 to deflect the diaphragm 60 in a direction that increases the volume of the suction chamber 58, a force in the opposite direction to the driving direction is applied to the connecting rod 61 due to the action of the jet 82. Become.

On the other hand, a support bolt 62 having an axis parallel to the throttle shaft 2 is screwed onto the outer surface of the throttle body 1, and a regulation lever 63 and a forced activation lever 64 are rotatably attached to the support bolt 62. Supported. That is, between the head 62a of the support bolt 62 and the throttle body 1, the support bolts 62 are arranged in order from the head 62a side.
A cylindrical collar 65 surrounding the collar 65, a disc-shaped regulating plate 66 that abuts the inner end of the collar 65, that is, the end closer to the throttle body 1, and an outer end, that is, the end far from the throttle body 1, that touches the regulating plate 66. Support bolt 6 so that they are in contact with each other
2, a cylindrical collar 67 surrounding the collar 67;
A regulating plate 68 interposed between the inner end of the throttle body 1 and the throttle body 1
The collar 65, the regulating plate 66, the collar 67, and the regulating plate 68 are fixed to the supporting bolt 62 by tightening the supporting bolt 62. The regulation lever 63 has a cylindrical portion 63a that coaxially surrounds the collar 65.
and a drum section 63b fixed to the outer end of the cylindrical section 63a.
The cylindrical portion 63a is the head 62 of the support bolt 62.
It is rotatably supported by a collar 65 between a and a regulating plate 66. The forced activation lever 64 consists of a cylindrical part 64a that coaxially surrounds the collar 67, and a drum part 64b fixed to the inner end of the cylindrical part 64a. It is rotatably supported by. The cylindrical portion 63a1 of the forced lever 63 and the cylindrical portion 64a of the forced activation lever 64 have collars 65.67 at their inner and outer ends.
Dust seals 63c and 64c are disposed on the sliding surfaces of the sliding parts, respectively, to prevent foreign matter from entering the sliding parts and to improve the reliability of the operation of the regulation lever 63 and forced activation lever 64.

The regulation lever 63 includes an adjustment screw 6 whose tip can come into contact with a contact arm 70 provided on the tenth motion lever 7.
The adjusting screw 69 and the contact arm 70 are connected to the tenth motion lever 7 so that the advancing and retracting positions can be adjusted.
are brought into contact with each other by rotating in the throttle valve closing direction 20. The throttle body 1 also has an abutting arm portion 70 when the tenth motion lever 7 rotates to a position where the throttle valve 6 is fully closed.
An adjustment screw 71 that abuts is screwed together so that the forward and backward positions can be adjusted.

The other end of the connecting rod 61 of the dash bot 56 is connected to the regulating lever 63, and the connection mode is such that the tenth motion lever 7 is in a state where the adjusting screw 69 is in contact with the contact arm 70. When the throttle valve is rotated in the closing direction 20, the diaphragm 60 to which the connecting rod 61 is connected is bent to increase the volume of the suction chamber 58.

The forced activation lever 64 is provided with an abutment arm 72, and an adjustment screw 73 whose tip can come into contact with the abutment arm 72 is screwed into the regulation lever 63 to enable adjustment of forward and backward positions. . The contact arm portion 72 and the adjustment screw 73 are brought into contact with each other by the biasing force of a spring 74 interposed between the throttle body 1 and the forced activation lever 64. spring 7
4 is a force that urges the tenth stroke motion lever 7 in the throttle valve opening direction 18 via the regulation lever 63 that is in contact with the forced activation lever 64 due to the contact between the contact arm portion 72 and the adjustment screw 73; When the operating lever 8 rotates from the fully closed position of the throttle valve 6 in the throttle valve opening direction 18, the regulation lever 63 and the forced activation lever 64 follow the operating lever 8 due to the spring 74. The retainer 80 of the dashbot 56 moves into the suction chamber 58.
When the side contacts the inner surface of the housing 57, the contact state between the adjustment screw 69 of the regulating lever 63 and the contact arm portion 70 is released.

In FIG. 5, an operating lever 8 and a forced activation lever 6 are shown.
4, when the operation lever 8 located at the position corresponding to the fully closed position of the throttle valve 6 is rotated in the throttle valve opening direction 18, the forced activation lever 64 is forcibly rotated, and the regulation lever 63 is rotated. A forced activation mechanism 75 is provided that forcibly rotates the tenth motion lever 7 and, in turn, the throttle shaft 2 in the throttle valve opening direction 18.

The forced activation mechanism 75 has a cam surface 76 provided on the side surface of the forced activation lever 64, and is pivotally supported by the operating lever 8 with an axis parallel to the throttle shaft 2 so as to move along the cam surface 76. It consists of a roller 77. Cam surface 76 and roller 7
7 is set to be in contact with each other between a position of the operating lever 8 corresponding to the fully closed position of the throttle valve 6 and a position where the operating lever 8 is slightly rotated in the throttle valve opening direction 18 from that state; The cam surface 76 is formed to rotate the forced activation lever 64 in the throttle valve opening direction 18 via a roller 77 in response to rotation of the operating lever 8 from the fully open position in the throttle valve opening direction 18. . On the other hand, the forced activation lever 64 is rotated in the throttle valve closing direction 18 within a range in which the cam surface 76 and the roller 77 are kept in contact by a stopper 64d fixed to the outer surface of the throttle body 1. This prevents the forced activation lever from rotating too much in the throttle valve closing direction and causes the roller 77 to ride on a portion of the forced activation lever 64 other than the cam surface 76, and further improves the reliability of the operation of the forced activation lever 64. Improvements are being made.

Next, the operation of this embodiment will be explained. When the operation lever 8 is rotated in the throttle valve opening direction 18 by operating the accelerator pedal with the step motor 52 fully open and stopped, the engagement arm 21a , 21b and 22
g and 22b, the tenth motion lever 7
That is, the throttle shaft 2 is rotated in the throttle valve opening direction 18, and the throttle valve 6 is rotated in the throttle valve opening direction 18 to a desired opening degree.

At this time, the step motor 52 is in a state where it can freely rotate together with the throttle valve 6, and the control lever 9 and each gear 43, 48 are rotated in accordance with the rotational movement of the throttle valve 6 in the opening direction.
．． The rotational power is also transmitted to the step motor 52 via the step motor 53, and the step motor 52 rotates freely.

The rotational movement of the operating lever 8 in response to the accelerator pedal operation is also transmitted to the 20th stroke motion lever 28 via the cam mechanism B, and the detection lever 29 is also transmitted to the 20th stroke motion lever 28 by the engagement of the engaging portions 36 and 37. That is, the detection shaft 27 rotates in the accelerator pedal depression direction 32. Therefore, the amount of rotation of the throttle shaft 2, that is, the throttle opening is detected by the throttle opening detector 46, and the amount of rotation of the operating lever 8, that is, the amount of accelerator operation is detected by the accelerator pedal operation amount detector 38.
It can be detected by

By the way, at the initial stage of rotating the throttle valve 6 from its fully closed position in the throttle valve opening direction 18,
Simply interlocking and connecting the operation lever 8 and the tenth motion lever 7 via the lost motion mechanism A will not provide enough starting force for the throttle shaft 2, and the initial rotational movement of the throttle shaft 2 will not be smooth. There may be cases where this is not the case. In such cases.

The initial rotational movement of the throttle shaft 2 is forcibly performed by the action of the forced activation mechanism 75. That is, when the operating lever 8 rotates to rotate the throttle valve 6 from its fully closed position, the roller 77 comes into contact with the pressure receiving surface 76 and is driven, thereby rotationally driving the forced activation lever 64. The rotation of 64 is transmitted to the regulating lever 63 which is in contact with the abutting arm 72 via the adjusting screw 73, and further includes the abutting arm 70 which is in contact with the adjusting screw 69 of the regulating lever 63. The signal is transmitted to the motion lever 7. Therefore, when the operating lever 7 is rotated for the first time, the tenth stroke motion lever 7 is forcibly rotated, and the initial rotational movement of the throttle shaft 2, that is, the throttle valve 6 from the fully closed position becomes smooth.

Furthermore, when the throttle valve 6 is rotated by the operation lever 8 to the opening degree, the throttle shaft 2, that is, the throttle valve 6 is provided with the first, second, and third return springs 19, 24, .
A spring force of 44 is acting on the closing side. Therefore, by relaxing the pulling force of the throttle wire 16, the operating lever 8 rotates in the throttle valve closing direction 20, and the throttle shaft 2 and the throttle valve 6 also rotate in the closing direction.

At this time, when the throttle valve 6 rotates to the vicinity of its fully closed position, the retainer 80 in the dashbot 56 moves into the suction chamber 5.
After the A setting screw 69 of the regulating lever 64 comes into contact with the contact arm 70, the damping force of the dashbot 56 due to the increase in the volume of the suction chamber 58 becomes the first. 10 act on the stroke motion lever 7, and the rotational speed of the throttle shaft 2 and the throttle valve 6 toward the closing side is moderately suppressed.

In addition, when the operation lever 8 is rotated in the throttle valve closing direction 20, the detection shaft 27 connected to the accelerator operation amount detector 38 via the lever 39 may not operate smoothly due to malfunction of the accelerator operation amount detector 38. Assume that the rotation does not occur. In this case, the cam 31a provided on the operating lever 8
Alternatively, 31b and the engagement pin 28b provided on the 20th stroke motion lever 28, or 28-b 22
The operating lever 8 can be rotated in the return direction 20 of the accelerator pedal by releasing the engagement with the throttle valve 1, and the throttle valve 6 can be reliably rotated toward the closing side.

As described above, when the throttle valve 6 is opened to a certain opening degree by operating the accelerator pedal and the throttle valve 6 is to be driven to the closing side for traction control or the like, the step motor 52 is operated. This step motor 5
2, the throttle shaft 2 and the throttle valve 6
can be rotated against the spring force of the tenth stroke motion spring 23 so that the engaging portions 21a, 21b of the operating lever 8 and the engaging portions 22a, 22b of the tenth stroke motion lever 7 are separated. Therefore, the throttle valve 6 can be driven in the closing direction regardless of the operation of the accelerator pedal.

The present invention has been described in detail above, but it goes without saying that the present invention is not limited to the above embodiments, and that various modifications can be made within the scope of the invention described in the claims. do not have.

As mentioned above, since the step motor 52 is configured to interlock with the throttle shaft 2 via a gear or the like,
The opening degree of the throttle valve 6 corresponds to the rotor rotation angle of the step motor 52.

FIG. 8 shows a circuit for driving the step motor 52. As shown in FIG. As mentioned above, the step motor 52 rotates the throttle valve 6 in the closing direction 20 against rotation of the throttle valve 6 in the opening direction 18 due to accelerator operation (see FIG. 2), and rotates the throttle valve 6 in the closing direction 20 (see FIG. 2). It operates to prevent excessive supply of fuel oil to the engine when the engine slips.

In this embodiment, the step motor 52 is provided with four-phase windings #1 to #4 and operates according to a predetermined excitation method such as two-phase excitation or 1-2 phase excitation. This step motor 52
The collector terminals of drive transistors 101 to 104 are connected to one end of the windings of each phase #1 to #4, and the bases of these drive transistors 101 to 104 are connected to a central processing unit (hereinafter referred to as CPU). ) 105 is connected (see FIG. 9, which will be described later). In addition, each phase #1 to #4
The other end of the winding is connected to an on-vehicle battery 107 via a chopping transistor 106. The chopping transistor 106 has its emitter connected to the battery 1.
07, its collector is connected to the windings of each phase #1 to #4, and its base is connected to an oscillation circuit (not shown) in the CPU 105. The base of the chopping transistor 06 is connected to a high frequency (for example, 20KH)
2 pulse signal is PWM (Pulse Width
Modulation) control, etc. Therefore, in such a circuit, the current of the battery 07 chopped by the chopping transistor 06 is supplied to the step motor 52, using the output pulses of the driving transistors 101 to 104 controlled by the CPU 105 as a timing reference, and the current of the battery 07 is chopped by the chopping transistor 06. 1~#
No. 4 winding is energized. In FIG. 8, diodes D1, D and Zener diode D22 protect driving transistors 101-104 and chopping transistor 06. Figure 9 shows these diodes D and D2.

This is a driving circuit in which D and the chopping transistor 106 are omitted, and the bases of the driving transistors 101 to 104 are connected to the output ports 01 to 04 of the CPU 105. The CPU 105 outputs control pulses directly to the drive transistors 101 to 104, and the CPU 105 outputs control pulses to the transistors 101 to 104 of the winding of the phase to be excited based on the count value of a register provided inside. Output. In such direct control by the CPU 105, no circuit is required for distributing control pulses to the driving transistors 101 to 104.
There is no need for a serial clock line connecting the CPU 105 and the pulse distribution circuit, and there is no locking of the step motor 52 due to disconnection of the line.
Wiring is also simplified.

FIG. 10 is a winding connection diagram in the stator of the step motor 52, and corresponds to diagram m8.

In FIG. 8, two power lines 108 and 109 are drawn out from the collector of the chopping transistor 106, and the power line 108 is branched into phase lines 111 and 113 for #1 and #3 phases, while the power line 109 is It is branched into phase lines 112 and 114 for #2 and #4 phases, and the windings of each layer #1 to #4 are energized. As shown in Figure 10, the stator is 8t! ! It has a salient pole of ii. These salient poles are arranged at equal intervals on the circumference in the order of 1 pole to 8 poles, 1 pole and 5 poles, 2 poles and 6 poles,
3 poles and 7 poles, 4 poles and 8 poles are facing each other.

When the step motor 52 is excited, the #1 phase and #3 phase are not energized at the same time, and the same is true for the #2 phase and #4 phase. Therefore, the windings of the #1 phase and #3 phase are Power line 1
08 is a common line, and a power supply line 109 is a common line for the #2 phase and #4 phase windings.

The CPU 105 (FIG. 9) controls the excitation of the stator by energizing the windings of each phase connected as described above. This control is performed by setting the phase to be excited in accordance with the count value of a register within the CPU 105. Table 1 below is a table showing an example of a case where this control is performed by 1-2 phase excitation.
Each winding #1 according to the count value 0 to 7 of the register 05
A signal “1” or “0” is set to be output to #4. In this case, when the count value increases from 0.1° to 7, the step motor 52 is rotated counterclockwise (CCW).
), while the count value is 7.6. By setting the case of a decrease such as →0 as clockwise (CW) rotation, switching of the rotation direction of the step motor 52 can also be controlled by the count value. In such a configuration, the register of the CPU 105 counts and outputs a signal corresponding to the count value from the output ports 01 to 04 based on the table in Table 1. Even if one of them is disconnected, signal output continues. For example, phase line 1
11 is disconnected, 0.6 and 7 are excluded from the count value, and 1.2, 3, 4.5, 1, 2. ... constitutes the count value. In this way, according to the control method of setting the phase to be excited according to the count value, fail-safe can be easily achieved. In this case, the step motor 52
On the other hand, the excitation of the phase in which the disconnection has not occurred is performed, which has the advantage that the step motor 52 can continue to be driven.

In the step motor 52 shown in Table 1 and above, failure of the drive transistors 101 to 104 or power supply lines 108, 1
09. If the phase lines 111 to 114 are disconnected or shorted, the motor will stop driving, making it impossible to control the supply of intake air or fuel mixture to the engine. Therefore, in this example,
A means to detect these failures and disconnections is adopted. These means will be explained below with reference to FIGS. 11 to 13.

FIG. 11 is a circuit diagram for detecting an abnormality on the drive transistors 101 to 104 side. Drive transistor 101~
104 is based on the output ports 0 to 0 of the CPU 105
4, respectively, and these transistors 1
Collectors 01 to 104 are connected to windings of each phase #1 to #4 of the stator of the step motor. Further, the emitters of the transistors 101 to 104 are grounded, and the transistors 101 to 104 are driven to excite the windings #1 to #4, respectively, based on the table shown in Table 1 mentioned above. These driving transistors 101 to 104
A detection line 115 is connected to the collector which becomes the output terminal of
- 118 are connected to each other, and the other ends of each detection line 115 - 118 are connected to detection input ports (1) - (4) of the CPU 105. CPU105 is this detection input port! It is detected whether or not there is a signal input from 1 to 4. And the human-powered detection boat I
- When I4 detects a signal input, it determines that the driving transistors 101 to 104 corresponding to that input port are normal, whereas when it does not detect a signal input, it determines that the driving transistors 101 to 104 corresponding to that input port are normal.
The system is equipped with a determination unit that determines that an abnormality occurs. In such a configuration, each driving transistor 101 to 104 is connected to the CPU 1.
05, and when there is no signal output from the collector of any one of the transistors 101 to 104, the CPU 105 can identify that transistor. Therefore, if any of the driving transistors 101 to 104 breaks down or if the harness wire that supplies current to the driving transistors 101 to 104 is disconnected or shorted, it is possible to detect the location where the problem usually occurs, and take countermeasures. Can be done competently. This countermeasure can be taken, for example, by a fail-safe method such as interrupting the supply of fuel oil or changing the setting of the counter value described above. Further, the CPU 105 can perform control so as not to drive the drive transistors 101 to 104 that do not have a signal output. For example, if there is no signal output from the driving transistor 101 corresponding to the #1 phase, the driving transistor 101 can be The rotation of the throttle valve 6 can be controlled by stopping the driving of the throttle valve 6 and driving the other driving transistors 102 to 104.

FIG. 12 shows a circuit for detecting abnormalities such as disconnections and short circuits in the phase lines 111 to 114. Phase lines 111 and 113 branch from the power line 108 and energize the #1 phase and #3 phase windings of the step motor 52, and phase lines 111 and 113 branch from the power line 109 and energize the #2 phase and #4 phase windings of the step motor 52. One end side of the detection line 119, 121, 120, 122 is connected to each phase line 112, 114 that supplies current to the line. Each detection line 119.121.120.1
The other end of 22 is the detection input port I of the CPU 105.
, I and I are connected to Si2 respectively 5 7
6 are connected, and the signals of the phase lines 111 to 114 are connected to the respective detection capacitors)1, I, I, 57.
6 It is designed to be input individually to 1B. CPU10
5 is the same as in the case of FIG.
, I , I , I 5 7 6
8. Therefore, the phase lines 111 to 114 corresponding to the same boat are determined to be normal, while the phase lines 111 to 114 corresponding to the boat are determined to be abnormal if no signal is input. The determination unit identifies the phase lines 111 to 114 that have caused an abnormality. Therefore, as in the case of Fig. 11, it is possible to take a fail-safe approach, and it is also possible to perform control based on Table 1 by omitting the count of the winding corresponding to the phase line determined to be abnormal. . In FIG. 12, two chopping transistors 106 and 110 are connected in parallel to the battery 107, and the chopping transistor 106 and
While the collector of is connected to the winding side of #1 and #3 phase,
The collector of the chopping transistor 110 is #2,
Connected to the winding side of #4 phase. By connecting the chopping transistors 06, 110 in parallel in this way, the load on each transistor 06, 110 is reduced, so failures and the like are reduced. In this case, abnormalities in the phase lines 111 to 114 can be detected even with one chopping transistor as shown in FIG. 8, but these are only optional matters.

Figure 13 shows step motor power lines 108 and 109.
This is a circuit that detects abnormalities such as disconnections and short circuits. One end of the detection line 123 is connected to the power line 108 on the winding side of the #1 phase and #3 phase of the step motor 52, and the detection line 124 is connected to the power line 109 on the winding side of the #2 phase and #4 phase. One end of is connected. The other ends of these detection lines 123 and 124 are connected to the detection input ports ■ and 11o of the CPU 105, and each port ■
, ■ are input with signals from respective power supply lines 10g, 10 and 109. The CPU 105 is the 11th
As in the case of Fig. 12, the power supply line 108, 109 is determined to be normal by the human input of the signal, while it is equipped with a determination unit that determines that it is abnormal if there is no signal input. Power line 108 or 109 that has an abnormality
is identified. Therefore, even in this case, it is possible to respond in a fail-safe manner in the event of an abnormality.

In this embodiment, in addition to monitoring the current supply system to the first winding of the step motor 52, the CPU 105 is also monitored. FIG. 14 shows a monitoring circuit for this CPU 105, and a watch spike 125 is connected to the CPU 105. Further, the output side of the AND gate 126 is connected to the base of the chopping transistor 106, and the CPU 1
05 is connected to one input terminal of the AND gate 126. The other input terminal of the AND gate 126 is connected to the output side of the watch spike 125. In such a configuration, the CPU 106 uses the AND gate 12
6 and also outputs a signal to the watch spike 125.

The watchtoge 125 monitors the CPU 106 based on the signal input from the CPU 106, and outputs a signal to the AND gate 126 if the signal is normal. As a result, the chopping transistor 106 is connected to the battery 1.
07 to the step motor 52, and the pulse motor 52
works normally.

On the other hand, if the watch thorn 125 is determined to be abnormal, the watch thorn 125 stops outputting to the AND gate 126. As a result, there is no output from the AND gate 126 to the chopping transistor 106, so the transistor 106 cuts off the power to the battery 107, and the step motor 52 stops. Therefore, C.P.
If U105 runs out of control, step motor 5
2 stops, the rotation control of the throttle valve by the motor 52 is eliminated, improving safety.

Control valves such as the throttle valve 6 and the choke valve (not shown) described above are provided in the air flow path to the engine of the axle, and are rotated individually by a step motor to control the air flow rate for sucking fuel oil. control. Therefore, the step motor that operates these control valves needs to be controlled to operate properly according to various external factors such as the battery voltage, the state of the axle being stopped or running, and the running speed. Hereinafter, cases will be explained separately based on an example in which this step motor control method is applied to the throttle valve 6.

(1) Control according to the opening degree of the control valve The throttle valve, choke valve, etc. operate to increase or decrease the opening area of the mixture passage or air passage by their rotation.
There is a correlation between the opening degree θTH of these valves and the opening area of the flow path. Further, the opening degree θTH of these valves is controlled by the operation of the step motor 52.
2, the operating angle θ and the valve opening degrees θ and H have a correlation. FIG. 15 is a characteristic diagram showing these correlations, and the characteristic curve 130 shows the change in operating angle θ of the step motor from the fully open state.
The characteristic curve 131 shows the change in the opening area of the throttle valve 6 with respect to the opening degree θTH. As shown in the figure, when the operating angle θ of the step motor is small (when the throttle valve opening θTH is large), the rate of change in the opening area is small, but the operating angle θ of the step motor becomes large (throttle valve opening θTH is large). degree θ
(TH is small), the rate of change in the aperture area becomes large. Since the rate of change in the opening area and the rate of change in the air flow rate are correlated with each other, in a region where the operating angle θ of the step motor is large, it is necessary to precisely control the operating angle θ.

By the way, the excitation control method for the step motor 52 is as follows.
There are a 1-phase excitation method, a 2-phase excitation method, and a 1-2 phase excitation method.

FIG. 16 shows the pulse rate, that is, P P S (Put
FIG. 2 is a torque characteristic diagram of the step motor output under the s Per 5econd ) control, in which a characteristic curve 132 shows the two-phase excitation method, and a characteristic curve 133 shows the 1-2 phase excitation method. As shown in the figure, the two-phase excitation method requires torque (i.e., working angle θ)
The 1-2 phase excitation method is controlled so as to change it in small increments, while the 1-2 phase excitation method is controlled so that the In other words, in the 2-phase excitation method, the operating step angle of the step motor is large, and the target operating angle is quickly reached, whereas in the 1-2 phase excitation method, the operating step angle is small, making it possible to precisely control the operating angle. .

The control described in item (1) is based on the above, and in the region where the rate of change of the opening area is small (that is, the region where the opening degree of the throttle valve is large), the step motor is driven by the two-phase excitation method, and the target angle of the throttle valve is On the other hand, in regions where the rate of change in the opening area is large (i.e., in regions where the opening degree of the throttle valve is small), the step motor is driven by the 1-2 phase excitation method to precisely control the opening area of the throttle valve. This is what we do. This switching between the 2-phase excitation method and the 1-2 phase excitation method is carried out as appropriate depending on the deviation between the current angle such as the opening degree of the throttle valve and the operating angle of the step motor and the target angle. In the case of
If it is less than 100°, driving can be performed using the 1-2 phase excitation method.

As a result, for example, when the axle slips, the throttle valve is rapidly throttled down using the 2-phase excitation method until the opening of the throttle valve reaches around 15 degrees, and after that, the throttle valve is throttled down at high speed by the 1-2 phase excitation method, which increases precision. Aperture can be performed. Note that since the characteristics of the two-phase excitation method and the one-phase excitation method are the same in terms of the magnitude of the operating step angle, the one-phase excitation method may be performed in place of the two-phase excitation method in this control.

(2) Control during 1-2 phase excitation drive The torque output from the step motor is different during 1-phase excitation and 2-phase excitation in the 1-2 phase excitation method. 1st
Figure 7 shows the duty ratio (r
It is written as DutyJ. ), in which a characteristic curve 134 shows the time of two-phase excitation, and a characteristic curve 135 shows the time of one-phase excitation. As shown in the figure, in order to obtain the same torque during one-phase excitation even when the same voltage is applied, a duty ratio larger than the duty ratio during two-phase excitation is required. As shown in FIGS. 1 to 4, the throttle shaft 2 of the throttle valve 6 is biased in the opening direction by the second return spring 24, and is driven by a step motor 52 that rotationally drives the throttle shaft 2 in the closing direction. The spring force of the return spring 24 is acting. step motor 5
2 maintains the stopped state of the throttle shaft 2 (that is, the throttle valve 6) against the spring force of the return spring 24 by the torque generated by energizing the stator coil, but when the torque during one-phase excitation is small, In this case, it may not be possible to hold the throttle shaft stopped, and since the holding position is different between one-phase excitation and two-phase excitation, step motor 52 may step out. In particular, driving by the 1-2 phase excitation method is in a region where the operating angle θ is large, as shown in item (1), and in this region, as shown in FIG. 18, the spring force of the return spring 24 acts strongly, The above disadvantages are likely to occur. This 1-
In order to maintain the stopped state by the two-phase excitation method, the duty of the excitation pulse is increased during l-phase excitation compared to two-phase excitation,
The purpose is to increase torque. The specific rate of increase in ruty is determined by the characteristic curve 134 shown in FIG. 17 and the characteristic curve 135.
The degree of overlap is good, and the duty during two-phase excitation is 1.
In the case of 5%, the duty during one-phase excitation is 22 to 22.
It is controlled to be 5%. By increasing the duty, the rotation of the throttle shaft 2 during one-phase excitation is eliminated, the throttle shaft 2 is held at a fixed position, and step-out due to positional deviation can be prevented. In the control described in item (1), switching between driving by the two-phase excitation method and driving by the 1-2 phase excitation method is performed depending on the opening degree of the throttle valve 6. FIG. 19 shows that the step motor 52 is driven by these drives.
It is a characteristic diagram of the torque output from the characteristic curve 136.
is the torque in the two-phase excitation method, and the characteristic curve 137 is 1-2
The torque in the phase excitation method is shown. As shown, 1-2
In the phase excitation method, the torque is smaller overall than in the two-phase excitation method, resulting in an imbalance with the torque of the two-phase excitation method.

Therefore, as another control method for driving by the 1-2 phase excitation method, the duty of the excitation pulse for driving by the 1-2 phase excitation method is
is increased to balance the drive torque by the two-phase excitation method. The specific increase rate of riuty is the 19th
This is to the extent that the characteristic curve 136 in the figure overlaps the characteristic curve 137.

(3) Chopping signal frequency control battery 10
The current of No. 7 is chopped by the chopping transistor 106 (or 106 and 110) and energized to each phase coil (see FIGS. 8 and 12). In order to perform this chopping, the chopping transistor 106 is connected to the CPU, and a chopping signal is input from the oscillation circuit of the CPU. This control section uses a signal having a frequency higher than the audible range frequency as the chopping signal. Signals in the audible range are highly sensitive to human sounds, and are perceived as oscillations, causing noise. In contrast, signals with frequencies above the audible range are not perceived as oscillations, and no noise is generated. The frequency of the chopping signal to be used is preferably 20 KHz or higher, and chopping can be controlled favorably by signals in such a high frequency range.

(4) Control when the step motor is stopped When the step motor is stopped and the voltage VB of the battery 107 fluctuates, control is performed to change the duty or pulse rate of the excitation pulse of the step motor in accordance with the fluctuation of the battery voltage VB. It is something. This is to maintain the opening degree of the throttle valve at a fixed position when the step motor is stopped. As mentioned above, the spring force of the return spring 24 acts on the throttle shaft 2 of the throttle valve, and in order to hold the throttle valve in a fixed position against this spring force, the step motor operates even when stopped. , battery 1
A current is applied from 07, and the excited state is maintained with a duty of 15%, for example.

If the battery voltage VB fluctuates in such a state, the supplied current fluctuates and the torque of the step motor fluctuates, and if it becomes less than the biasing force of the return spring, the opening degree of the throttle valve cannot be maintained constant.

This control is to change the duty or pulse rate of the excitation pulse to the step motor in accordance with fluctuations in the battery voltage Vn. In addition, in order to perform this control, fluctuations in the battery voltage are monitored and the battery voltage VB
When the pulse rate deviates from a predetermined range, the duty or pulse rate is changed. With such control, even if the battery voltage fluctuates when the step motor is stopped, the throttle valve can maintain a constant opening degree.

For example, when the battery voltage is 14V, the duty is 60%.
and when the battery voltage drops to 12V, Dut
Increase y to, for example, 80% to stabilize the motor torque when stopped.

(5) Control when the battery voltage fluctuates When the battery voltage VB fluctuates, the duty of the chopping signal is changed in accordance with the voltage fluctuation to control the output of a constant torque. Also, this D
In addition to the UTY control, the pulse rate is changed to output a constant torque. for example,
The former control is applied when the fluctuation range of battery voltage is small, and the latter control is applied when there is a large fluctuation in battery voltage that cannot be compensated for by the former control.

FIG. 20 is a characteristic diagram in which the duty of the chopping signal and the average current passed from the battery to the step motor are plotted according to the voltage value of the battery voltage VB. As shown, as battery voltage VB decreases, the average current to the step motor also decreases. Since the output torque of the step motor also decreases due to this decrease in current, in this case, the duty of the excitation pulse of the chopping signal that excites the step motor is increased to maintain a constant value as shown by the double-dotted dots in the figure. control so that the average current of is applied to the step motor. Thereby, even if the battery voltage Vo fluctuates, the step motor can stably output a constant torque.

On the other hand, the duty of the chopping signal has an upper limit of 100%, and as shown in FIG. 21, when the battery voltage Vn decreases significantly, there is a limit to torque compensation by increasing the duty. FIG. 22 is a characteristic diagram of the output torque when the step motor is controlled by the pulse rate, and as the pulse rate is decreased, the torque increases. Therefore, if there is a drop in battery voltage that cannot be compensated for by duty control, control is performed to reduce the pulse rate and output a constant torque. Therefore, water control is a control that increases the duty when the battery voltage decreases, and decreases the pulse rate when there is a large decrease in the battery voltage that cannot be compensated for by duty control. It is. FIG. 23 shows the critical point at which duty control and pulse rate control are switched, and constant torque is maintained by performing pulse rate control at the hatched portion.

In this way, this control monitors the battery voltage VB and performs duty control and pulse rate control based on fluctuations in the voltage value. Since no circuit is required, the control system can be simplified and the control can be made easier and more reliable.

In the above-mentioned pulse rate control, it is also possible to change the pulse rate value according to fluctuations in battery voltage, and to continue control at the same pulse rate value within a certain fluctuation range of battery voltage. FIG. 24 shows a characteristic diagram of an example of this control, in which the battery voltage Vn is 16V to 10V.
The step motor is driven at a pulse rate of 600 until around V, and when it drops to around 10V, it is driven at a pulse rate of 400. Driving at this 400 pulse rate continues if the battery voltage VB tends to decrease, but if the battery voltage VB increases and returns to around 12V, for example, driving is switched to the 600 pulse rate. ing. By setting such a pulse rate history, control with little loss becomes possible even if the battery voltage increases or decreases.

In addition to the above-described UTY control and pulse rate control, if the battery voltage further decreases, control is performed to cut off the power supply to the step motor.

The above controls are effective within a predetermined range of voltage values, but if the battery voltage drops below a predetermined voltage value, these controls cannot output not only the predetermined operating torque but also the holding torque. .

FIG. 25 shows the output torque of the step motor as the battery voltage fluctuates, and the torque can be maintained at a constant load line by increasing the duty. However, there is a limit to increasing the duty or changing the pulse rate, and when the battery voltage drops beyond this limit, the power supply to the step motor is stopped. FIG. 26 and FIG. 27 show specific examples of the battery voltage at which the step motor is de-energized.

FIG. 26 shows how to obtain the torque for starting the step motor, and this torque is determined by the motor required torque. In a range where the battery voltage VB has decreased to a certain extent, it is possible to cope with this by increasing the duty and decreasing the pulse rate in order to obtain the required motor torque. However, when the battery voltage drops beyond the controllable range of these duty control and pulse rate control, the step motor cannot output the motor required torque, and therefore, the power supply to the step motor is cut off. Note that the range from the throttle drive load line to the motor required torque shown in the figure is a range in which the throttle valve is not driven by the output of the step motor.

FIG. 27 shows how to obtain the torque for stopping the step motor. The stopping torque is to maintain the throttle valve at a constant opening degree against the spring force of the return spring that biases the throttle valve in the opening direction, and the battery voltage Vs also increases with respect to this stopping torque output. If it drops more than necessary,
Cut off the power to the step motor. By cutting off the power supply to the step motor in this way, it is possible to save power from the battery power source. Such control of cutting off power to the step motor can also be performed by simply monitoring the battery voltage, making it possible to simplify the system and facilitate control.

(6) Control of the steady state (stopped state/operating state) of the step motor The duty of the chopping signal is controlled to be changed between when the step motor is stopped and when the step motor is activated. Specifically, the chopping signal when the step motor is stopped is
This is to control y to be smaller than the duty during operation.

In a steady state in which the step motor can be started, a predetermined current is supplied from the battery even when the step motor is stopped, and this current supply holds the throttle shaft against the spring force of the second return spring 24. The average current applied when the step motor is stopped is sufficient to output a torque that resists the spring force, and the duty of the chopping signal when the step motor is stopped is smaller than the duty of the chopping signal when the step motor is in operation. . This makes it possible to save battery power. In addition, as a specific value, if the step motor's duty is 50% when it is operating, it is possible to select a duty of around 15% when it is stopped.
In particular, it is not limited to this value.

(7) Control of the transient state between stopping and operating the step motor When starting the step motor from a stopped state, control is performed to increase the value of the current flowing to the step motor at the time of starting. The stopped state of the step motor is maintained by balance with the spring force of the return spring of the throttle valve, and when rotating the throttle valve from this stopped state, the spring force of the return spring and the magnetic force of the stator magnet in the step motor are required. It is necessary to drive the step motor against this, and the load on the step motor is large at the beginning of startup. In order to quickly transition from the load state at the beginning of startup to a steady startup state, control is performed to increase the current flowing at the beginning of startup. This increase in current can be achieved by increasing the duty of the signal. FIG. 28 shows the characteristics of the torque (pull-1n) for starting the step motor. In this control, by increasing the current flowing while keeping the voltage constant, the characteristic curve 138 changes to The pull-in torque is increased by increasing the pull-in torque. FIG. 29 shows a timing chart of an example of current increase control due to duty increase. In the stopped state, electricity is supplied with a duty of 15%, and when a start request signal is input in this state, the pulses to the step motor are
It can be changed to 70%. This duty7
The 0% signal continues for several pulses, and after transitioning to a steady operating state, the duty is switched to 50%. Under steady-state operating conditions, the load is small due to inertia, and relatively
Since it is possible to drive with a small torque, the duty is reduced according to the load. Such control of the current applied to the step motor at the beginning of startup has better responsiveness than acceleration/deceleration control based on PPS increase/decrease, and the required torque can be quickly obtained. Figure 30 shows the starting duty required by the step motor when the throttle valve is fully closed (opening 0') and fully open (opening 80°). In order to start the pulse motor against this large load, the above-mentioned control is performed at a higher duty (for example, 80%).

(8) Step motor energization control When the step motor does not need to be driven, control is performed to cut off the energization to the step motor.

For example, if the throttle valve 6 can be maintained at a predetermined angle simply by operating the accelerator pedal, and there is no excess or deficiency in the amount of intake air or the amount of air mixture into the engine, there is no need to drive the step motor. In such a case, control is performed to cut off the energization to the step motor. To cut off the current, use one of the following methods. In addition, the following means are CPU10
This is done by commands such as 5.

■ Set the duty of the chopping signal to 0.

■ Chopping transistor 106°110 (8th
(see Figure 12).

By stopping the operation of the chopping transistor, electricity is cut off from the battery 107 to each phase winding of the stator.

■ Turn off the power to all driving transistors 101 to 104. By stopping the operation of all the drive transistors, the power supply to each phase winding of the step motor is cut off.

(2) Turn off the power to the chopping transistors 106 and 110 and all driving transistors 101 to 104.

The above control makes it possible to reduce power consumption of the battery power source of the step motor.

(9) Chopping signal control This is control to divide the chopping signal into two systems.

The chopping signal is output from the chopping transistor to each phase winding of the stator of the step motor via the power supply line. This chopping transistor is
As shown in Figure 2, by connecting two units in parallel to the battery 107, the chopping signal is divided into two systems, and the chopping transistor 106 is #1.
Output to the #3 phase winding and chopping transistor 1
10 is #2. Output to #4 phase winding. #1 phase and #3 phase are not energized at the same time, and the same is true for #2 phase and #4 phase. Even if they are connected as a pair to each chopping transistor, it will not interfere with the operation of the step motor. It never occurs.

Further, by using the chopping transistors in parallel in this manner, the load on each transistor is halved. Therefore, the chopping transistor generates less heat and has temperature stability.

(10) Control when starting the starter When the starter switch is ON, the power supply to the step motor is cut off, but when the starter switch is ON and the engine is started, the power supply to the step motor is turned off after a certain delay time has elapsed. control to do so. The starter switch consumes a large amount of battery power, so turn it on.
Sometimes the battery voltage drops so drastically that the step motor cannot obtain the voltage to drive it. For this reason, when the starter switch is turned on, power to the step motor is uniformly cut off to bring the step motor into a full-time state, thereby preventing consumption of battery power.

On the other hand, when the battery voltage recovers after the engine has completely exploded and the step motor can be driven, the step motor is energized after a certain delay time. This delay time takes into account the time it takes for the battery voltage to recover to a value that allows driving the step motor.

FIG. 31 shows a circuit diagram for performing such control. Battery 107 is connected to starter motor 152 via starter switch 150 and relay switch 151. Relay switch 151 is starter switch 150
When the relay switch 151 is turned on, the starter switch 150 is closed and the starter motor 152 is energized, while when the starter switch 150 is opened when the engine is started, the relay is closed. Switch 151 is also opened and power to starter motor 152 is cut off. In the figure, 153 is an electrical control unit (hereinafter referred to as ECU), which has a clock that measures time at the same time as the starter switch 150 is opened and closed. In addition, a predetermined delay time is set in the ECU 153 in advance, and the measurement time measured by the clock is compared with the delay time, and when the measured time reaches the delay time, the step motor is controlled to restart driving. do.

FIG. 32 shows a timing chart with the above configuration,
When the starter switch is turned on, the battery voltage Vn rapidly decreases. On the other hand, when the starter switch is turned OFF, the battery voltage VB gradually recovers. ECU15
3, the step motor is energized after a predetermined delay time (for example, 0.1 to 0.25 ec) after the starter switch is turned off. This delay time is the time required for the battery voltage VB to recover to an extent that the step motor can be driven, and is set in advance based on experiments and the like.

(11) Control during abnormality When the step motor drive circuit is abnormal, the power supply from the battery is cut off. FIG. 33 shows a circuit diagram for performing this control.
55 are provided. The cut switch 155 is turned on so that its contact is closed when the step motor 52 is normal, but when the step motor 52 is abnormal, the contact is opened and operates to disconnect the battery 107 and the step motor 52. In the illustrated example, a relay switch is used as the cut switch 155, but other switches such as a solenoid switch may be used. This cut switch 155 is connected to the ECU to control the above operation. FIG. 34 shows an example of a detection circuit for detecting an abnormality in the drive circuit of the step motor 52. At the same time, one set of #1 that is not energized
The 1st phase line and the #33 phase line, the #22 phase line and the #44 phase line form an exclusive OR circuit 156.
The output side of this exclusive OR circuit 156 is connected to the input terminal of an AND circuit 157, so that abnormality in energization to the windings is detected by taking the logical product of these. It has become. Also, AND circuit 15
An excitation signal 158 such as one-phase excitation, two-phase excitation, etc. is also input to 7, and an abnormality in excitation of each phase winding different from the excitation signal is also detected. The signal from the AND circuit 157 is input to the CK terminal of the flip-flop circuit 159, and then from the Q terminal of the flip-flop circuit 159 to the E
Output to CU 1.53.

The ECU 153 is provided with a cut switch control section, which operates the cut switch as described above based on a signal input from the flip-flop circuit 159. In this way, the detection circuit determines whether the step motor 52 is abnormal or normal, and if it is determined to be abnormal, the cut switch 155 is controlled to cut off the conduction between the battery 107 and the step motor 52, thereby preventing abnormal operation of the step motor 52. Abnormalities in the underlying engine control can be prevented, and power consumption of the battery 107 can also be prevented.

〔Effect of the invention〕

As explained above, the present invention connects the transistors that excite each phase winding of the step motor directly to each output port of the control means, thereby simplifying the circuit for driving the step motor and simplifying the wiring. In addition, even if one phase is not excited due to wire breakage, the step motor can be driven by excitation of other phases.

[Brief explanation of drawings]

FIG. 1 is a front view of a throttle control device according to an embodiment of the present invention, FIG. 2 is a view taken along the ■ arrow in FIG. 1, FIG. 3 is a view taken along the line ■-■ in FIG. Fig. 5 is a view taken from the v-■ arrow in Fig. 3, Fig. 6 is a partial perspective view of the bridge member 25b, and Fig. 7 is a cross section showing the adjustment screw of the intermediate gear. Figure 8 is a circuit diagram for driving the step motor, Figure 9 is a circuit diagram showing the connection between the step motor and the driving transistor, Figure 10 is a winding connection diagram of the stator of the step motor, and Figure 11 is a circuit diagram showing the connection between the step motor and the driving transistor. The figure shows a circuit diagram for detecting an abnormality in the driving transistor, Fig. 12 is another circuit diagram for driving a step motor, Fig. 13 is a circuit diagram for detecting an abnormality in the power supply line of the step motor, and Fig. 14 shows a circuit diagram for detecting an abnormality in the step motor power supply line. A circuit diagram showing the CPU monitoring circuit, Fig. 15 is a characteristic diagram showing the relationship between the operating angle of the step motor and the opening degree of the throttle valve, and Fig. 16 is a characteristic diagram showing the output torque of the step motor under pulse rate control. Fig. 17 is a characteristic diagram showing the output torque of 1-2 phase excitation, Fig. 18 is a characteristic diagram showing the relationship between the operating angle of the step motor and the spring force of the return spring, and Fig. 19 is a characteristic diagram showing the output torque of 1-2 phase excitation and 2-phase excitation. A characteristic diagram showing the output torque of excitation, Figure 20 is a characteristic diagram showing the relationship between step motor duty and current, Figure 21 is a characteristic diagram showing the relationship between battery voltage and step motor duty, and Figure 22 is a characteristic diagram showing the relationship between step motor duty and current. A characteristic diagram showing the output torque of the step motor during rate control, Fig. 23 is a characteristic diagram showing the switching point between duty control and pulse rate control, Fig. 24 is a characteristic diagram showing history control using pulse rate, and Fig. 25 is a characteristic diagram showing the relationship between the battery voltage and the output of the pulse motor, Fig. 26 is a characteristic diagram showing control when the battery voltage decreases with respect to the starting torque of the step motor, and Fig. 27 is a characteristic diagram showing the stopping torque of the step motor. Fig. 28 is a characteristic diagram showing control at the initial stage of starting the step motor, Fig. 29 is a timing chart showing an example of current increase control due to duty increase, and Fig. 30 is a characteristic diagram showing control of the throttle valve. A characteristic diagram showing the starting duty according to the opening degree, Fig. 31 is a circuit diagram for controlling the starter switch operation, Fig. 32 is a timing chart of the circuit in Fig. 31, and Fig. 33 shows step motor abnormality. FIG. 34 is a circuit diagram for detecting an abnormality in the step motor. 101-104... Drive transistors, 105...
・CPU, 106, 110... Chopping transistor, 107... Battery, 108, 109...
Power line, 111, 114... Phase line, 115~
124...Detection line, 125...Watch spike,
126... AND gate, 130... Characteristic curve of throttle valve opening degree, 131... Characteristic curve of opening area,
132...Characteristic curve of two-phase excitation, 133...1-2
Characteristic curve of phase excitation, 134...Torque during 1-phase excitation of 1-2 phase excitation, 135...Torque during 2-phase excitation of 1-2 phase excitation, 136...Torque of 1-2 phase excitation Torque, 137
...Torque of two-phase excitation, 138,139...pυl
l-1n) Luk, 150...Starter switch, 1
51... Relay switch, 152... Starter motor, 153... Engine control unit, 15
4...Lead wire, 155...Cut switch, 6.
...Exclusive OR circuit, 7...AND circuit, 59...Flip-flop circuit

Claims (1)

[Claims] In a method of driving a control valve of an in-vehicle engine energized by a spring with an output torque generated by energizing a step motor, the control valve is adjusted to correspond to the torque required for the stop state and the torque required for the operating state of the control valve. A control valve control method for an on-vehicle engine, characterized in that the duty ratio of pulses of the step motor is switched between a stopped state and an operating state.